This Phase I STTR application represents a partnership between a university-based research group (Imaging Science and Information Systems [ISIS] Center, Department of Radiology, Georgetown University) and a small business specializing in open-source software development (Kitware, Inc. of Clifton Park, NY). Over the past 1 1/2years, the ISIS Center has been developing a prototype image-guided surgery system called IGBiopsy to enhance the precision of instrument placement for minimally invasive abdominal interventions. This system incorporates a soon-to-be commercially available magnetic tracking system and specially designed needles whose tip position can be monitored. The software for this prototype is based on the Visualization Toolkit (VTK), an open-source software system developed and now supported by Kitware. This prototype software and hardware will be used as the starting point for the work proposed here. The specific aims are: 1. Integration. As a demonstration project, we will integrate the graphical user interface for image-guided abdominal interventions developed by Georgetown with the Insight Registration and Segmentation toolkit (ITK) developed by Kitware and others. 2. Pre-clinical evaluation. The software developed in Aim 1 will be evaluated in a pre-clinical study using a liver respiratory motion phantom already developed by Georgetown. The accuracy of the system in assisting the physician in placing a biopsy needle into a simulated liver lesion will be evaluated. These tests and Specific Aim 3 will also be used to evaluate the accuracy of the magnetic tracking hardware in the interventional suite. 3. Clinical evaluation. The system will be further evaluated using a cadaver study in the interventional suite. The accuracy of the system in assisting the physician in targeting selected points in the liver will be evaluated. If the Phase I work proposed here is successful, Kitware and Georgetown University will be in a position to develop an open-source software framework for image-guided surgery in a Phase II effort.